A polycarbonate-polyorganosiloxane copolymer (hereinafter sometimes abbreviated as “PC-POS”) has been expected to be widely used in various fields such as the field of electrical and electronic equipment and the field of automobiles because of its high impact resistance, chemical resistance, flame retardancy, and so forth. In particular, the use of the PC-POS has been expanding in housings for a cellular phone, a smart phone, a mobile personal computer, a tablet, a portable remote terminal, and the like; in an illumination cover and a construction material; in housings for electronic equipment which require visibility such as a digital camera and a video camera; in protective equipment such as a police shield, a helmet visor, and a sport protective equipment, and in other commodities. These are expected to be used not only in usual conditions such as at room temperature but also at low temperature such as in a cold district as well as in an outdoor environment.
A homopolycarbonate whose raw material is 2,2-bis(4-hydroxyphenyl)propane [common name: bisphenol A] has been generally used. A polycarbonate-polyorganosiloxane copolymer using a polyorganosiloxane as a copolymerizable monomer has been known for improving the physical properties of the homopolycarbonate such as flame retardancy and impact resistance. It has been known that the polycarbonate-polyorganosiloxane copolymer has higher flame retardancy and impact resistance as compared with the homopolycarbonates made with bisphenol A and the like (Patent Document 1).
In Patent Document 2, a polycarbonate-polyorganosiloxane copolymer whose transparency is improved is disclosed, wherein a total light transmittance, a Haze value, and the like are evaluated.
In Patent Document 3, a polycarbonate-polyorganosiloxane copolymer whose color tone is improved is disclosed. In Patent Document 3, it is taught that by decreasing content of a certain component in the polycarbonate-polyorganosiloxane copolymer, not only excellent heat stability can be obtained but also color difference due to residence time at the time of injection molding can be made smaller.